Making Panel data problem

[Curtis Chou]

Hello
I have a problem that making panel data. However, I still fail to get I wanted.

///My code

//1.ONE data
use http://www.stata-press.com/data/r14/overlap1, clear
foreach i in x1 x2{
destring `i', replace force
replace `i'=0 if `i' == .
replace `i'=2 if `i' == .a
}

gen t = _n
cd "D:"
save "1.dta", replace

//2. TWO data
cd "D:"
webuse reshape1, clear
gen t = 1
save m1, replace
forvalues i =2(1)15{
replace t = `i'
save m`i', replace
}


//3 Merge ONE and TWO data
cd "D:"
use "1.dta",clear
forvalues i =1(1)15{

merge 1:m t using "m`i'.dta"
drop _merge
}
end
/////////
My ideal Panel data as follows:

t ONE DATA TWO DATA
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3

[Curtis Chou]

I am sorry, I want to generate these data by data1(use http://www.stata-press.com/data/r14/overlap1, clear) and data2 (webuse reshape1, clear)
please help me to construct Panel data like under:

n ONE DATA t TWO DATA
1 1
1 2
1 3
2 1
2 2
2 3

[Curtis Chou]

I use this way, but i only merge t =1 and report "variable t does not uniquely identify observations in the master data"

/////
forvalues i =1(1)15{

merge 1:m t using "m`i'.dta"
drop _merge
}

[Curtis Chou]

I am sorry, please drop id in two data set
////
use http://www.stata-press.com/data/r14/overlap1, clear
drop id
foreach i in x1 x2{
destring `i', replace force
replace `i'=0 if `i' == .
replace `i'=2 if `i' == .a
}

gen t = _n


cd "D:\論文 summary\台大研究\中心資料整理"
save "1.dta", replace

webuse reshape1, clear
drop id
gen t = 1
save m1, replace
foreach i in 2 3 4 5 6 7 8 9 10 11 12 13 14 15{
cd "D:\論文 summary\台大研究\中心資料整理"

//gen t = `i'
replace t = `i'

save m`i', replace
}
end
use "1.dta",clear
forvalues i =1(1)15{
merge 1:m t using "m`i'.dta"
drop _merge
}
///
However, stata always report "variable t does not uniquely identify observations in the master data"

the result shows Stata merge fail except t = 1

seq x1 x2 t sex inc80 inc81 inc82 ue80 ue81 ue82
1 1 1 1 0 5000 5500 6000 0 1 0
1 1 1 1 1 2000 2200 3300 1 0 0
1 1 1 1 0 3000 2000 1000 0 0 1
2 1 0 2
3 1 2 3
4 0 2 4
1 0 1 5
2 0 2 6
3 1 1 7
4 1 2 8
5 2 1 9
6 2 2 10
1 0 2 11
2 0 1 12
3 0 0 13
4 2 2 14
1 5 8 15

[Hemanshu Kumar]

Your merge fails after the first one because after the first merge, there are many observations in the master dataset with t=1.

Consider this instead of your current loop for merging:

forvalues i = 1/15 {
    merge 1:m t using m`i'
    preserve
        keep if _merge == 3
        save merged`i', replace
        local mergefiles `mergefiles' merged`i'
    restore
    drop if _merge == 3
    drop _merge
}

clear
append `mergefiles'